1. Field of the Invention
This invention relates in general to wireless communications systems, and more specifically, to an advanced voice service known as “Press-to-Connect” for wireless communications systems.
2. Description of Related Art
Advanced voice services (AVS), such as two-way half-duplex voice calls within a group, also known as “Press-to-Talk,” “Push-to-Talk,” PTT or P2T, have enormous revenue earnings potential for wireless networks, such as cellular networks and personal communications systems (PCS) networks.
Currently, there are three major approaches employed in providing advanced voice services such as P2T in wireless networks. One approach requires the installation of a dedicated private network, parallel to the wireless network, to support the group-based voice services. NEXTEL uses such a system, based on a solution developed by MOTOROLA known as IDEN. However, a dedicated private network is costly to install and maintain and is employed by a few public wireless carriers. Also, the IDEN system is non-standard, and hence cannot be used in standard wireless communications networks, such as those based on GSM (Global System for Mobile Communications) and CDMA (Code Division Multiple Access).
Another approach is based on Voice over IP (VoIP) technologies. While this approach promises compliance with newer and emerging standards, such as GPRS (General Packet Radio Service), UMTS (Universal Mobile Telecommunications System), etc., it does not provide a solution for carriers employing wireless networks based on existing standards, such as GSM, CDMA, etc. However, even for the newer standards, solutions based on VoIP have serious drawbacks, including slower call setup, significant overhead, increased susceptibility to packet losses, low bit rate voice coders, and significant modifications to the mobile handset. There is a need, instead, for solutions that require only minimal upgrades to the handset.
Still another approach is that defined in co-pending and commonly-assigned P.C.T. utility patent application Serial Number PCT/US03/16386, filed on May 23, 2003, by Gorachand Kundu, Ravi Ayyasamy, and Krishnakant Patel, entitled DISPATCH SERVICE ARCHITECTURE FRAMEWORK, which application is incorporated by reference herein. In this approach, group-based voice services are provided by a dispatch gateway or real-time exchange that interfaces to the wireless network to provide the group-based voice services therein, wherein both the dispatch gateway and mobiles that use the group-based voice services communicate with each other using call setup and in-band signaling within the wireless network.
Notwithstanding these innovations, there is a need in the art for other advanced voice services that comply with existing and emerging wireless standards and provide superior user experiences. The present invention aims to satisfy this need by providing an advanced voice service known as “Press-to-Connect” for wireless communications systems.